Xe-129 NMR of adsorbed xenon is shown to be useful for studying properties of zeolites and related materials such as pore structure (pore dimensions, pore geometry, defects, intergrowth, etc.), multicharged cations (compensating cations or extraframework aluminum, etc.), and encumbering species (coadsorbed phases, coke deposits, etc.). The technique has been extended to the study of microporous polymers.